The present invention relates to packaging and packaging machines therefor.
Cylindrical objects such as drinks cans and bottles are frequently packed in packs of twenty four. They are assembled in an array of four columns and six columns on a cardboard tray and the whole is wrapped in a polythene sleeve which is heated to cause the sleeve to shrink around the pack and lock the objects in their positions on the tray. The packs are then stacked on a pallet and transported to a warehouse for distribution.
A packaging machine for effecting the continuous packaging of the objects includes an elongate conveyor system onto which the objects are fed en masse at the upstream end. The conveyor passes between guides which constrain the objects to proceed only six abreast. The conveyor passes through a marshalling station which marshals the objects into spaced groups with each group arrayed in six rows and four columns. Each group is then fed through a tray assembly station in which a cardboard tray blank is fed under the array. Adhesive material is applied to various flaps of the blank and the blank is then erected using predefined fold lines to form a shallow tray. The array of objects on the tray continue along the conveyor for a period sufficient to allow the adhesive to take effect and then passed through a wrapping station. At the wrapping station, the leading end of a sheet of plastics is fed under the tray and a set of bars carry the trailing edge of the sheet forward over the top of the pack and in front of it so that the advancing pack passes over the trailing end and the sheet becomes completely looped about the pack in the form of a sleeve with the trailing and leading end portions of the sheet overlapping.
The sleeved pack then passes through a heating station. At the heating station the overlapping end portions of the sheet pass over heated rollers which seal the two portions together. Air jets are directed at opposite open ends of the sleeve to inflate the sleeve and simultaneously heat is applied to cause the sleeve to shrink relatively uniformly about the tray and the array of objects so as to lock the array of objects in position on the tray.
The pack of objects are then transported to a stacking station where the packs of objects are stacked on a pallet for subsequent transportation.
It is an object of the invention to provide an improved packaging and packaging machine.
According to the invention there is provided a trayless close-packed planar array of filled cans or bottles enveloped in a sleeve of heat shrinkable plastics shrink-wrapped around the cans or bottles and covering the cylindrical ends of all the cans or bottles, the cans or bottles being arranged in an odd number of rows, with each alternate row having the same even number of cans or bottles and each intervening row having the same odd number of can or bottles, the sleeve being of sufficient thickness to hold the cans or bottles generally in their close-packed formation when carried unsupported.
According to the invention there is further provided a marshalling station for marshalling cylindrical objects arriving at the station into spaced arrays having different numbers of objects in different rows, the station comprising a reservoir for temporarily storing said objects as they arrive, a plurality of parallel conveyor belts, each belt being arranged to receive one row of said objects from said reservoir, a pair of arresting means located on opposite sides of each belt to be engaged by the leading object of each row, each arresting means being movable in the same direction as the belts but at a slower speed than the belts, different arresting means associated with different belts moving at different speeds so that during the period that said arresting means are operational, the objects on different belts move at different speeds, whereby when the arresting means disengage said objects, the plurality of belts will accelerate away from said marshalling station, an array of objects in which different rows contain different numbers of objects.
According to the invention there is still further provided a collating station for collating an array of twenty five objects arranged in a first formation into a second formation, comprising first conveying means for conveying the objects, row wise, in the first formation in which the objects are arranged in seven rows, the middle three rows having three objects each and the remaining rows having four objects each, pusher means for engaging the trailing column of objects of the array to displace the array in the same direction as being moved by the first conveyor means across a stationary surface and onto second conveyor means and then disengaging the array, the pusher means having projections which provide additional displacement of alternate rows of the array by an amount not exceeding the radius of the object, and guide means having converging surfaces to compress the array as it is being driven across the stationary surface into a close packed array in which each alternate row has four objects and each intervening row has three objects and thereby define said second formation.